Gold Districts of California

FOLSOM

Location. This district is in northeastern Sacramento County. It was mainly a
dredging field that extended from the town of Folsom southwest along the south side of the
American River to Fair Oaks, south through the town of Natoma to Nimbus and then west to
the east border of what is now Mather Air Force Base. The dredged area is approximately 10
miles long in a southwest direction and up to seven miles wide. The Folsom district has
also been known as the American River district.

History. The region around Folsom and Mormon Bar was extensively placer-mined
during the gold rush, with minor lode mining. The area was originally settled in 1849 and
first known as Negro Bar. The present town was laid out in 1855 by T. D. Judah for the
Sacramento Valley Railroad and named for Captain J. L. Folsom, quartermaster of
Stevenson's Regiment. Numerous Chinese worked the region from the 1860s through the 1890s.
A primitive grab-dredger was active at Natoma in 1894. Bucket-line dredging began at
Folsom in 1898 and soon became. a major industry. Most of the dredging companies were
merged into Natomas Consolidated of California in 190@. This firm, later known as the
Natomas Company, was the principal operator in the district. The company designed and but
its own dredges at extensive shops in the town of Natoma. In 1916, 11 active dredges
yielded more than $2 million worth of gold. From 1927 to 1952, several other operators
joined Natomas in dredging the district.

Dredging operations were curtailed during World War II but were resumed on a major
scale shortly afterward. However, increasing costs, the depletion of dredging ground, and
changing land values caused the dredging operations to be gradually curtailed. By 1960
there was only a single active dredge, and this was shut down in February 1962. Large
portions of the dredged-over areas are now occupied by defense industries, such as the
Aerojet-General Corporation and Douglas Aircraft Company plants, and by housing tracts.
Folsom, one of the largest dredging fields in California, has a total output estimated at
$125 million. Approximately one billion cubic yards of gravel were dredged by the Natomas
Company.

Geology. Recent stream gravels lie in and adjacent to the present American
River. To the south are sand and gravel deposits of the Victor Formation (Pleistocene) and
silt, sand and some gravel of the Laguna Formation (Plio-Pleistocene). These are underlain
by andesite of the Mehrten Formation (Pliocene). The paying gravels are either in or along
the American River and near the lower contacts of the Laguna and Mehrten Formations.
Digging depths ranged from 30 to 110 feet and recoveries from 100 to 200 per yard with
gold valued at $35 per ounce. Minor amounts of platinum were. recovered. There are a few
narrow gold-quartz veins in greenstone east of the town of Folsom.